CoAuthors

Kaoru Ichikawa (RIAM, Kyushu University, Japan)

Waveforms of satellite altimeters are often contaminated in coastal areas by strong radar reflection from calm water in semi-closed bays or weak reflection from lands. Several algorithms have been proposed to retrieve the sea surface height (SSH) avoiding these contamination in a waveform, but such retrievals are independent for each single waveform and waveforms of the adjacent points have never been referred. In this study, along-track AltiKa 40 Hz data near Tsushima Island, Japan, are processed at once for each cycle to retrieve the coastal SSH accounting contamination in waveforms of the adjacent points. Since the reflection from a point source results in a parabolic shape in an echogram with latitude versus altimeter tracking gate, extremely strong echo values with parabolic shapes are first masked. For each tracking gate at each point, lost echo by land is roughly compensated based on the ratio of the land area in the altimeter’s footprint ring, then the Brown model is fitted to each modified waveform. The retrieved SSH shows reasonable values with no abrupt changes along tracks.